https://github.com/dekz/foundry-playground

Foundry playground
https://github.com/dekz/foundry-playground

Last synced: about 1 month ago
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Foundry playground

• Host: GitHub
• URL: https://github.com/dekz/foundry-playground
• Owner: dekz
• Created: 2022-01-28T09:04:36.000Z (about 3 years ago)
• Default Branch: master
• Last Pushed: 2022-01-31T22:19:37.000Z (about 3 years ago)
• Last Synced: 2024-04-17T02:56:43.964Z (10 months ago)
• Language: Solidity
• Homepage:
• Size: 13.7 KB
• Stars: 28
• Watchers: 2
• Forks: 1
• Open Issues: 2
• Metadata Files:
  • Readme: README.md

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README

        
# Foundry playground

## FakeERC20

Replaces ERC20 token code with a fake implementation that allows for balance overrides whilst maintaining existing balances.

No more messing about with pretending to be token whales and praying they don't move funds.

No more pretending to be a rich contract and finding out its used somewhere down the stack.

⚠️ Warning: This increases the gas cost of all transactions using faked tokens.

```solidity

    // Fake out WETH

    FakeERC20 fakeToken = fakeOutERC20(address(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2));

    fakeToken._setBalance(address(this), 1e18);

    IERC20Token(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2).balanceOf(address(this)); // => 1e18

```

To get an idea of what's happening under the hood, take a look at the call trace.

```

[PASS] testFakeERC20() (gas: 93054)

Traces:

  [93054] ERC20TokenFakerTest::testFakeERC20()

    ├─ [2534] 0xc02a…6cc2::balanceOf(0xb4c79dab8f259c7aee6e5b2aa729821864227e84)

    │   └─ ← 0

    ├─ [0] VM::etch(0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc3, ORIGINAL ERC20 CODE)

    │   └─ ← ()

    ├─ [0] VM::etch(0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2, FAKED ERC20 CODE)

    │   └─ ← ()

    ├─ [51986] 0xc02a…6cc2::_setBalance(0xb4c79dab8f259c7aee6e5b2aa729821864227e84, 10000000000000000000)

    │   ├─ [534] 0xc02a…6cc3::balanceOf(0xb4c79dab8f259c7aee6e5b2aa729821864227e84)

    │   │   └─ ← 0

    │   └─ ← 10000000000000000000

    ├─ [2836] 0xc02a…6cc2::balanceOf(0xb4c79dab8f259c7aee6e5b2aa729821864227e84)

    │   ├─ [534] 0xc02a…6cc3::balanceOf(0xb4c79dab8f259c7aee6e5b2aa729821864227e84)

    │   │   └─ ← 0

    │   └─ ← 10000000000000000000

```